Production of colorations on materials



Patented Feb. 19, 1935 PRODUCTION .OF COLORATIONS ON MATERIALS GeorgeHolland Ellis, Spondon, near Derby, England, assignmto CelaneseCorporation or America, a'corporatlon of Delaware No Drawing.Application January 25, 1933, Se-

rial No. 653,476. 10, 1932 3 Claims.

This invention relates to the production of effects on textile materialsand more particularly to the production of efiects on such materialsmade or or containing cellulose acetate or other cellulose esters.

In the production of discharge or resist effects on textile materials itis customary either to apply a ground colour to the material and then toprint the coloured material with a composition containing a dischargingagent or to apply the discharge composition to the material before theapplication of the ground colour so that colouration by the groundcolour does not take place in the printed areas. Where coloured patterneifects are desired, colouring matter resistant to the discharging agentand having afilnity for or capable of being fixed on the material isincorporated in the discharge composition.

In the production of pattern efiects on materials comprising an organicester of cellulose, however, it has been found that the application of acomposition containing a discharging agent to the coloured material doesnot always give complete discharge of the ground colour as readily as isdesirable. Where a deeply coloured pattern, e. g. navy blue, is to beproduced, this may not be of such great importance, but where a white ordelicately coloured pattern is required it is a matter of the utmostimportance that the ground colour should be completely discharged in theprinted areas.

It has now been found that good discharge of a ground colour onmaterials made of or containing cellulose esters can readily be obtainedif, after colouration with the ground colour but prior to theapplication of the discharge composition, the material is subjected to asaponification treatment for the cellulose ester.

According to the present invention, t erefore, discharge or dischargeresist effects are produced on materials made of or containing celluloseesters by a process comprising a saponification of the cellulose esterportions of the materials after colouration, but before efiecting thedischarge.

Among saponifying agents which may be employed for the process of thepresent invention are caustic soda, caustic potash, sodium or potassiumcarbonate, sodium silicate, or trisodium phosphate. These agents may, ifdesired, be in aqueous or alcoholic solution. They may further beemployed in conjunction with any other desired substances,- such iorexample as swelling agents for the material. A particularly suitablesaponiiying agent is a 2 to 10% solution of caustic soda in a mixture ofalcohol and water In Great Britain February The saponifying agent may beapplied by any convenient method, e. g. by padding or other method ormechanical impregnation. After application of the saponifying agent thematerial is preferably steamed, aged, or dried to bring about or tocomplete saponification to the desired extent.

The amount of saponification necessary to lead to improved discharges oncellulose acetate materials is small. For the best results, however, ithas been found desirable to saponify so that there is a loss in weightof at least 5%, e. g. 10 or or more. In the case of other esters anequivalent degree of saponification may be employed.

The discharge of the ground colouration may be effected with the aid ofany suitabledischarging agent, for example reducing discharging agentssuch for example as aldehyde or ketone sulphoxylates, particularly zincformaldehyde sulphoxylate, hydrosulphites, stannous salts, such forexample as stannous chloride, or oxidation discharges, e. g. chloratesor chromates. The discharge compositions may contain any other desiredingredients, e. g. swelling agents, catalysts and/or delustring orrelustring agents for the cellulose ester portion of the material, suchfor example as alcohols, phenol, anthraquinone, hy-

droquinone and urea.

' Where coloured pattern eilects are to be produced the compositions maycontain dyestuffs resistant to the discharging agent but having anafiinity for or capable of being fixed on the saponified fibre, ordyestufi components or leuco compounds which may subsequently bedeveloped or oxidized on the fibre. Thus-for example wheresaponification has been carried out only to a small extent any or theusual dyestufis employed in the colouration of cellulose ester materialsand which are resistant to the discharging agent may be used forcolouring the discharge composition. Where saponiflcatlon has beencarried out to a greater extent dyestufis having an amnity for cottonmay be employed for this purpose.

The discharge composition may be applied to the material in anyconvenient manner. Thus for example it may be applied by printing orthrough stencils.

As has been indicated the process of the present invention may beapplied to material of any cellulose ester capable of saponification.Thus for example it may be applied to materials made of or containingcellulose acetate, cellulose formate, cellulose propionate or cellulosebutyrate. It is however equally applicable to materials containing thesecellulose esters in admixture with other textile fibres, e. g. celluloseether fibres, regen erated cellulose, cotton, wool or silk fibres. Inthis connection, by suitably adjusting the degree of saponification ofthe cellulose ester, it is possible to obtain very valuable effects onmaterials containing other fibres in addition to the cellulose ester.Thus for example a mixed fabric containing cellulose acetateand cottonmay be cross dyed with dyestuffs having an affinity for celluloseacetate and with dyestufis having an afflnity for cotton, the celluloseacetate saponified until it acquires afiinity for cotton dyestuffs, andthe material then printed with a discharge composition containing adyestuif resistant thereto and having an affinity for cotton, when acoloured pattern effect on a cross dyed ground is obtained. v

The following examples illustrate the invention without being in any waylimitative:

Example 1 Parts Zinc formaldehyde sulphoxylate"; 25 Methylated Spirits10 Ethyl lacta l0 Gum arabic thickening The printed goods are thendried, aged for 5 to '7 minutes in a Mather and Platt ager and finallywashed thoroughly and dried or subjected to any other treatments whichmay be desirable or requisite. An excellent white discharge print isobtained on a red ground, thedischarge being more complete than adischarge attained under parall conditions on unsaponified materials.

Example 2 A woven cellulose acetate fabric dyed a redviolet shade with2:4-dinitrobenzene-azo-4-diethylaminobenzene is padded with an 8%solution of caustic soda, squeezed with rollers which are so adjustedthat the fabric retains approximately of its weight of liquor, andpassed Parts Sodium formaldehyde sulphoxylate 10 Potassium carbonate 12Metlrylated spirit 10 Gum thickening and water 88 The fabric is thendried, steamed in a Mather and Platt ager or ina vat steamer, washed oi!and dried, when an excellent white discharge is obtained on thered-violet ground. If coloured discharge effects are required, vatdyestuifs may be incorporated in the above printing paste.

Example 3 A fabric consisting of equal parts of cotton and celluloseacetate, and dyed in contrasting shades with 2nitro-4-methyl-benzene-am-para-xyli-. dine on the acetate, and ChlorazolFast Blue ZBN (see page 345 of Color Index) on the cotton, is paddedwith a 6% solution of sodium carbonate, the conditions being such thatthe fabric takes up 100% of its own weight of liquor. It is then driedon a stenter and steamed in a Mather and Lott ager or in a vat steamer,and finally p'rinted according to either of the discharge processes ofExamples 1 or 2, steamed or aged, and washed and dried, when excellentdischarges are obtained on a two colour ground.

What I claim and desire to. secure by Letters Patent is:

1. In the production of discharge eifects on materials made of orcontaining cellulose esters, saponifying the materials after colourationwith a ground colour but prior to discharge of that ground colour.

2. Process according to claim 1, characterized in that the celluloseester is cellulose acetate.

3. Process for the production of discharge ef-' fects on materials madeof or containing cellulose acetate, which comprises saponifying thematerials after coloration with a ground color, to such an extent thatthe cellulose acetate loses between 5 and 15% of its weight, andthereafter discharging the ground color.

. GEORGE mm) muss.

